Mixer assembly and tail gas aftertreatment package

Abstract

A mixer assembly comprises a shell and a mixer at least partially located in the shell. The shell comprises a mounting part for mounting a urea nozzle, and the urea nozzle is used for spraying atomized urea liquid drops to the mixer; at least one surface of the mixer is coated with a hydrophobic coating, so that the mixer becomes a hydrophobic surface with a contact angle of more than 90 degrees with the urea droplets. According to the utility model, the hydrophobic coating is arranged, so that the risk that urea liquid drops are crystallized is reduced, and the urea crystallization resistance is improved. The utility model further discloses a tail gas after-treatment package with the mixer assembly.

Description

Background Art

[0002] With the continuous upgrading of emission regulations, higher requirements are put forward for the concentration of harmful substances in engine exhaust. In order to reduce the concentration of harmful substances, the exhaust after-treatment system also increases the injection amount of urea accordingly. However, the risk of urea crystallization brought about by the increase in urea injection amount is also increasing.

[0003] During the cold start of the vehicle, the exhaust gas generated from the engine is transferred to the exhaust gas after-treatment package through a pipeline or a cylinder structure for conversion treatment. Generally, the atomized urea droplets are sprayed through the urea nozzle in the mixer assembly to fully mix with the exhaust gas, so as to achieve the conversion of harmful components in the exhaust gas in the selective catalytic reducer (SCR) to meet the requirements of emission regulations. In order to achieve full mixing of urea with the exhaust gas in the mixer assembly, different part structures are usually designed inside it according to the requirements of gas mixing. However, on the one hand, due to the low surface temperature of the part structure or between the crystallization temperature during the cold start process, the atomized urea droplets are prone to urea crystallization. On the other hand, the part structure is generally made of stainless steel, and its material surface itself has hydrophilic properties, so that urea particles are easily adsorbed on the material surface. Therefore, when the atomized urea droplets sprayed from the urea nozzle collide with the surface of the part structure, the urea droplets will adhere to the surface of the part. As the urea particles continue to enrich, urea crystallization will eventually occur on the surface of the part.

[0004] However, there is still room for improvement in the technical solutions in the related art. Utility Model Content

[0005] The utility model aims to provide a mixer component and an exhaust gas post-processing package with good urea crystallization resistance.

[0006] To achieve the above-mentioned purpose, the utility model adopts the following technical solution: a mixer assembly, comprising: a shell and a mixer at least partially located in the shell; the shell comprises a mounting portion for mounting a urea nozzle, and the urea nozzle is used to spray atomized urea droplets onto the mixer; at least one surface of the mixer is coated with a hydrophobic coating, so that it becomes a hydrophobic surface with a contact angle of greater than 90° to the urea droplets.

[0007] As a further improved technical solution of the utility model, the hydrophobic coating is coated on the inner and outer surfaces of the mixer.

[0008] As a further improved technical solution of the utility model, the mixer includes a first plate located in the shell, a second plate located downstream of the first plate along the airflow direction, and a third plate located downstream of the second plate along the airflow direction, the first plate includes a blocking portion and a partition connected to the blocking portion, the mixer assembly includes an air inlet cavity, an air outlet cavity and a mixing cavity connecting the air inlet cavity and the air outlet cavity, the air inlet cavity, the mixing cavity and the air outlet cavity are used to allow exhaust gas to circulate, the The mixing chamber and the air intake chamber are located on both sides of the partition, and the partition includes a connecting hole connecting the air intake chamber and the mixing chamber; the shell includes a mounting portion for mounting a urea nozzle, and the urea nozzle is used to spray urea droplets into the mixing chamber, so that the exhaust gas entering the mixing chamber and the urea droplets collide with each other and mix in the mixing chamber; the mixer assembly also includes a porous plate located in the mixing chamber and above the partition, and the porous plate is provided with a plurality of urea crushing holes for crushing urea.

[0009] As a further improved technical solution of the utility model, two ends of the porous plate are respectively fixed to the blocking portion and the third plate.

[0010] As a further improved technical solution of the utility model, the blocking portion extends in a vertical direction, the partition portion extends in a horizontal direction, and the porous plate is parallel to the partition portion.

[0011] As a further improved technical solution of the present invention, the second plate is provided with a first fixing portion fixed on the inner wall of the shell and a first arc-shaped protrusion protruding forward from the middle of the first fixing portion into the mixing chamber, and the first arc-shaped protrusion is provided with a plurality of first air flow holes; the second plate is provided with a first recessed space located behind the first arc-shaped protrusion; the third plate is provided with a second fixing portion fixed on the inner wall of the shell and a second arc-shaped protrusion protruding forward from the middle of the second fixing portion at least partially into the first recessed space, and the second arc-shaped protrusion is provided with a plurality of second air flow holes; the mixer assembly includes an arc-shaped cavity located between the first arc-shaped protrusion and the second arc-shaped protrusion.

[0012] As a further improved technical solution of the utility model, the first fixing portion is provided with a first slot, and the first arc-shaped protruding portion is provided with a second slot;

[0013] The partition is provided with a first protruding piece inserted into the first slot and a second protruding piece inserted into the second slot.

[0014] As a further improved technical solution of the utility model, the partition portion is provided with a first arc-shaped groove that matches the shape of the first arc-shaped protrusion, and the second protrusion protrudes into the first arc-shaped groove.

[0015] As a further improved technical solution of the present invention, the first arc-shaped protrusion spans across the second plate in the vertical direction, and the first fixing portion is located on both sides of the first arc-shaped protrusion.

[0016] As a further improved technical solution of the present invention, the second arc-shaped protrusion does not cross the third plate along the vertical direction, and the second fixing portion is located around the second arc-shaped protrusion.

[0017] As a further improved technical solution of the utility model, the first fixing part is provided with a plurality of first air flow holes; the second fixing part is provided with a plurality of second air flow holes.

[0018] As a further improved technical solution of the utility model, the second arc-shaped protrusion is punched from the middle of the third plate, and the third plate is provided with a first tearing hole corresponding to the upper edge of the second arc-shaped protrusion and a second tearing hole corresponding to the lower edge of the second arc-shaped protrusion.

[0019] As a further improved technical solution of the present utility model, the length of the first arc-shaped protrusion along the vertical direction is greater than the length of the second arc-shaped protrusion along the vertical direction.

[0020] As a further improved technical solution of the utility model, the first fixing portion is provided with a third slot, the second arc-shaped protruding portion is provided with a fourth slot; and the blocking portion is provided with a fifth slot;

[0021] The perforated plate is provided with a third protrusion inserted into the third slot, a fourth protrusion inserted into the fourth slot, and a fifth protrusion inserted into the fifth slot.

[0022] As a further improved technical solution of the utility model, the porous plate is provided with a second arc-shaped groove that matches the shape of the first arc-shaped protrusion, and the fourth protrusion protrudes into the second arc-shaped groove.

[0023] As a further improved technical solution of the utility model, the hydrophobic coating is coated on the outer surface of at least one part of the shell, the first plate, the second plate, the third plate and the porous plate.

[0024] The utility model also discloses an exhaust gas after-treatment package, which includes a diesel oxidation catalyst component, a diesel particulate filter component located downstream of the diesel oxidation catalyst component and connected to the diesel oxidation catalyst component, a mixer component located downstream of the diesel particulate filter component and connected to the diesel particulate filter component, and a selective catalytic reduction component located downstream of the mixer component and connected to the mixer component, wherein the mixer component is the aforementioned mixer component.

[0025] Compared with the prior art, the utility model reduces the risk of crystallization of urea droplets and improves the ability to resist urea crystallization by providing the hydrophobic coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a three-dimensional schematic diagram of the exhaust gas aftertreatment package of the utility model in one embodiment.

[0027] Figure 2 yes Figure 1 A three-dimensional diagram from another angle.

[0028] Figure 3 yes Figure 1 Partial exploded view of the .

[0029] Figure 4 It is a three-dimensional schematic diagram of the mixer assembly of the utility model.

[0030] Figure 5 yes Figure 4 A three-dimensional diagram from another angle.

[0031] Figure 6 yes Figure 4 Exploded three-dimensional diagram.

[0032] Figure 7 yes Figure 6 A three-dimensional exploded view of the second plate and the third plate.

[0033] Figure 8 yes Figure 4 Right view of .

[0034] Fig. 9 is along Figure 8 Schematic diagram of the cross section along line AA.

[0035] Fig.10 It is a cross-sectional schematic diagram of a mixer component of the utility model in one embodiment after being coated with a hydrophobic coating.

[0036] Fig.11 It is a cross-sectional schematic diagram of another embodiment of the mixer assembly of the utility model after being coated with a hydrophobic coating.

[0037] Fig.12 It is a schematic diagram of the contact angle formed between the gas-liquid interface and the liquid-solid interface at the junction of gas, liquid and solid when a liquid droplet reaches equilibrium on the surface of a solid. DETAILED DESCRIPTION

[0038] The exemplary embodiments will be described in detail below in conjunction with the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the utility model. Instead, they are only examples consistent with some aspects of the utility model as detailed in the attached claims.

[0039] The terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0040] In the present utility model, unless otherwise clearly stipulated and limited, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or may include the first and second features not being in direct contact but being in contact through another feature between them. Moreover, the first feature being "above", "above" and "above" the second feature includes the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature includes the first feature being directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature. The exemplary embodiments of the present utility model are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments may complement or combine with each other.

[0041] The terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0042] Please refer to Figures 1 to 3As shown, the utility model discloses an exhaust gas aftertreatment package 100 for treating the exhaust gas of an engine to reduce the emission of harmful substances. The exhaust gas aftertreatment package 100 includes an oxidation catalyst component (DOC) 1, a diesel particulate filter component 2 (DPF) located downstream of the oxidation catalyst component 1 and connected to the oxidation catalyst component 1, a mixer component 3 located downstream of the diesel particulate filter component 2 and connected to the diesel particulate filter component 2, and a selective catalytic reduction component (SCR) 4 located downstream of the mixer component 3 and connected to the mixer component 3. In the illustrated embodiment of the utility model, the oxidation catalyst component 1, the diesel particulate filter component 2 and the mixer component 3 are detachably connected by a clamp to facilitate maintenance and replacement. In the illustrated embodiment of the utility model, the oxidation catalyst component 1, the diesel particulate filter component 2, the mixer component 3 and the selective catalytic reduction component 4 are arranged in a straight line.

[0043] Please combine Figures 3 to 9 As shown, the mixer assembly 3 includes a housing 31 and a mixer at least partially located in the housing 31. In the illustrated embodiment of the utility model, the mixer includes a first plate 41 located in the housing 31, a second plate 42 located downstream of the first plate 41 along the exhaust gas flow direction, and a third plate 43 located downstream of the second plate 42 along the exhaust gas flow direction. The mixer assembly 3 includes an air inlet cavity 32, an air outlet cavity 33, and a mixing cavity 34 connecting the air inlet cavity 32 and the air outlet cavity 33. The air inlet cavity 32, the mixing cavity 34, and the air outlet cavity 33 are used to allow the exhaust gas to circulate.

[0044] In the illustrated embodiment of the present invention, the shell 31 is cylindrical and made of metal material; of course, in other embodiments, the shell 31 may also be other shapes, such as an elliptical shape.

[0045] The first plate 41 includes a blocking portion 411 and a partition 412 connected to the blocking portion 411. In the illustrated embodiment of the present invention, the blocking portion 411 and the partition 412 are perpendicular to each other, the blocking portion 411 extends in a vertical direction, and the partition 412 extends in a horizontal direction.

[0046] The mixing cavity 34 and the air intake cavity 32 are located on two sides (eg, upper and lower sides) of the partition 412 , and the partition 412 includes a connecting hole 4121 connecting the air intake cavity 32 and the mixing cavity 34 .

[0047] The housing 31 includes a mounting portion 35 for mounting a urea nozzle 5. The urea nozzle 5 is used to spray urea droplets into the mixing cavity 34. The exhaust gas and the urea droplets entering the mixing cavity 34 have at least a main component along opposite directions (e.g., an upward component) in their respective flow directions. The exhaust gas and the urea droplets having the main component collide with each other in the mixing cavity 34 and are mixed.

[0048] In the illustrated embodiment of the present invention, the mixing chamber 34 includes a first space 341 located between the first plate 41 and the second plate 42, a second space 342 located between the second plate 42 and the third plate 43, and a third space 343 located downstream of the third plate 43.

[0049] The partition 412 is fixed to the middle and lower part of the second plate 42. The partition 412 includes a plurality of first protrusions 4122, at least one second protrusion 4123 and a first arc-shaped groove 4124. The second protrusion 4123 protrudes backwards and extends into the first arc-shaped groove 4124.

[0050] The partition 412 is further provided with a first protrusion 4125 protruding upward to enhance the structural strength. The communication hole 4121 is at least partially provided on the first protrusion 4125 .

[0051] The mixer assembly 3 further includes a porous plate 6 located in the mixing chamber 34 and above the partition 412 . The porous plate 6 is provided with a plurality of urea crushing holes 60 for crushing urea.

[0052] In the illustrated embodiment of the utility model, the two ends of the porous plate 6 are respectively fixed to the blocking portion 411 and the third plate 43. The porous plate 6 is parallel to the partition 412. Specifically, the porous plate 6 is provided with a plurality of third protrusions 63, at least one fourth protrusion 64 and a plurality of fifth protrusions 65. The porous plate 6 is also provided with a second arc-shaped groove 62 having the same shape as the first arc-shaped groove 4124, and the fourth protrusion 64 protrudes into the second arc-shaped groove 62. The porous plate 6 is also provided with a second protrusion 66 protruding upward to enhance the structural strength. The urea crushing hole 60 is at least partially arranged on the second protrusion 66.

[0053] The second plate 42 is provided with a first fixing portion 421 fixed on the inner wall of the shell 31 and a first arc-shaped protrusion 422 protruding forward from the middle of the first fixing portion 421 into the mixing chamber 34. The first arc-shaped protrusion 422 spans the second plate 42 in the vertical direction, that is, the first arc-shaped protrusion 422 extends to the top and bottom ends of the second plate 42 in the vertical direction. The first fixing portion 421 is located on both sides of the first arc-shaped protrusion 422. The first arc-shaped protrusion 422 is provided with a plurality of first airflow through holes 4221. The first fixing portion 421 is provided with a plurality of first airflow through holes 4211 for airflow to pass through. The second plate 42 is also provided with a first recessed space 423 located behind the first arc-shaped protrusion 422. In addition, the first fixing portion 421 is provided with a first slot 4212 and a third slot 4213. The first arc-shaped protrusion 422 is provided with a second slot 4222 and a fourth slot 4223. The blocking portion 411 is provided with a fifth slot 4111 .

[0054] The third plate 43 is provided with a second fixing portion 431 fixed to the inner wall of the housing 31 and a second arc-shaped protruding portion 432 protruding forward from the middle of the second fixing portion 431 at least partially into the first recessed space 423. The second arc-shaped protruding portion 432 is provided with a plurality of second airflow holes 4321. The second fixing portion 431 is provided with a plurality of second airflow holes 4311 for airflow to pass through. The second arc-shaped protruding portion 432 does not cross the third plate 43 along the vertical direction, that is, the second arc-shaped protruding portion 432 does not extend to the top and bottom ends of the third plate 43 along the vertical direction. The second fixing portion 431 is located around the second arc-shaped protruding portion 432. In the illustrated embodiment of the present invention, the second arc-shaped protrusion 432 is punched from the middle of the third plate 43, and the third plate 43 is provided with a first tearing opening 433 corresponding to the upper edge of the second arc-shaped protrusion 432 and a second tearing opening 434 corresponding to the lower edge of the second arc-shaped protrusion 432.

[0055] During assembly, the first protrusion 4122 of the partition part 412 is inserted into the first slot 4212 of the first fixing part 421, and the second protrusion 4123 of the partition part 412 is inserted into the second slot 4222 of the first arc-shaped protrusion 422, and the first arc-shaped groove 4124 and the second arc-shaped groove 62 are both fitted with the first arc-shaped protrusion 422.

[0056] Similarly, the third protrusion 63 of the porous plate 6 is inserted into the third slot 4213 of the first fixing portion 421, the fourth protrusion 64 of the porous plate 6 is inserted into the fourth slot 4223 of the first arc-shaped protrusion 422, and the fifth protrusion 65 of the porous plate 6 is inserted into the fifth slot 4111 of the blocking portion 411. In order to improve the tightness of the combination, welding may be required at the plug-in position.

[0057] The mixer assembly 3 includes an arc-shaped cavity 40 located between the first arc-shaped protrusion 422 and the second arc-shaped protrusion 432. The length of the first arc-shaped protrusion 422 along the vertical direction is greater than the length of the second arc-shaped protrusion 432 along the vertical direction.

[0058] During operation, the airflow flows into the air inlet cavity 32 on the left side; the airflow flows into the space located in the partition 412 under the blocking portion 411; the airflow located below the partition 412 then flows upward into the first space 341 through the connecting hole 4121; when the injection condition is met, the urea nozzle 5 located above the first space 341 sprays atomized urea droplets downward; at this time, the exhaust gas flowing upward and the urea droplets sprayed downward are mixed in the first space 341; the crushed urea particles follow the airflow and directly hit the The second plate 42 generates ammonia gas; the porous plate 6 can break the urea particles that hit it into smaller particles; then, the airflow is distributed to both sides under the guidance of the first arc-shaped protrusion 422, and of course a part of the airflow directly passes through the first airflow hole 4211 and the first airflow through hole 4221; then, the airflow entering the arc-shaped cavity 40 is distributed to both sides again under the guidance of the second arc-shaped protrusion 432, and of course a part of the airflow directly passes through the second airflow hole 4311 and the second airflow through hole 4321. Finally, the airflow can be relatively evenly distributed on the inlet end face of the selective catalytic reducer assembly (SCR) 4.

[0059] The second plate 42 of the utility model is provided with a first arc-shaped protrusion 422 protruding forward into the mixing chamber 34, and the third plate 43 is provided with a second arc-shaped protrusion 432 protruding forward at least partially into the first recessed space 423. By providing the first arc-shaped protrusion 422 and the second arc-shaped protrusion 432, the airflow can be guided to both sides, which is conducive to improving the mixing uniformity of urea and exhaust gas, thereby improving the ability to resist urea crystallization. In addition, the porous plate 6 of the utility model is provided with a plurality of urea crushing holes 60 for crushing urea, and the urea crushing holes 60 can crush urea into smaller particles, thereby improving the ability to resist urea crystallization.

[0060] The inventors have found through research and analysis of the urea crystallization mechanism and a large number of literature that increasing the contact angle of the material surface is beneficial to reducing the crystallization phenomenon of the droplets. Fig.12 As shown, when the droplet reaches equilibrium on the surface of the solid, the angle between the gas-liquid interface and the liquid-solid interface at the junction of the gas, liquid and solid phases is called the contact angle. Generally speaking, when the contact angle of the material surface to the droplet is less than 90°, it is called a hydrophilic surface; when the contact angle of the material surface to the droplet is greater than 90°, it is called a hydrophobic surface. Based on the above analysis, the inventors have concluded that coating the material surface with a hydrophobic coating 7 (including but not limited to painting, spraying, spin coating, dipping and pulling, etc.) to increase the contact angle of the material surface is an effective method to reduce urea crystallization.

[0061] In the illustrated embodiment of the present invention, the hydrophobic coating 7 can be coated on the surface of the parts on the exhaust gas after-treatment package 100 that come into contact with the urea droplets, including but not limited to the surface of the mixer assembly 3 (for example, the surface of the shell 31, the surface of the first plate 41, the surface of the second plate 42, and the surface of the third plate 43); and the surface of the porous plate 6, etc.

[0062] Please combine Fig.10 As shown, in one embodiment of the utility model, the hydrophobic coating 7 can be coated on the outer surface of the shell 31, the outer surface of the first plate 41, the outer surface of the second plate 42, the outer surface of the third plate 43, and the outer surface of the porous plate 6.

[0063] Please combine Fig.11 As shown, in another embodiment of the present invention, the hydrophobic coating 7 can be coated on the inner and outer surfaces of the shell 31, the inner and outer surfaces of the first plate 41, the inner and outer surfaces of the second plate 42, the inner and outer surfaces of the third plate 43, and the inner and outer surfaces of the porous plate 6.

[0064] In the illustrated embodiment of the present invention, the base materials of the housing 31, the first plate 41, the second plate 42, the third plate 43 and the porous plate 6 are all made of stainless steel, wherein the thickness of the stainless steel is between 0.9 mm and 2.5 mm (including the end values). The thickness of the hydrophobic coating 7 is ≥ 20 μm. The temperature resistance of the hydrophobic coating 7 is ≥ 500°C.

[0065] The utility model applies the hydrophobic coating 7 to the surface of the part in contact with the urea droplets, so that the contact angle of the material surface is greater than 90°, that is, the original hydrophilic surface is changed to a hydrophobic surface. In the process of the urea droplets and the exhaust gas being fully mixed, when the atomized urea droplets collide with the surface of the above-mentioned part, since the surface of the part is coated with the hydrophobic coating 7, the atomized urea droplets are not easy to adhere to the surface of the part. Therefore, compared with the product whose surface of the part is not coated with the hydrophobic coating 7, the utility model can greatly reduce the generation of urea crystals.

[0066] Those skilled in the art will appreciate that, without conflicting with industry terminology, the term "water" used in the present invention is intended to indicate a certain liquid, rather than being equivalent to H2O in the chemical field.

[0067] In addition, the above implementation modes are only used to illustrate the present invention and are not intended to limit the technical solutions described in the present invention. The understanding of this specification should be based on the technical personnel in the relevant technical field. Although this specification has described the present invention in detail in conjunction with the above implementation modes, ordinary technical personnel in the field should understand that technical personnel in the relevant technical field can still modify or make equivalent substitutions to the present invention, and all technical solutions and improvements thereof that do not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A mixer assembly, characterized in that: include: A shell and a mixer at least partially located in the shell; the shell includes a mounting portion for mounting a urea nozzle, and the urea nozzle is used to spray atomized urea droplets onto the mixer; at least one surface of the mixer is coated with a hydrophobic coating to make it a hydrophobic surface with a contact angle of greater than 90° to the urea droplets.

2. The mixer assembly according to claim 1, characterized in that: The hydrophobic coating is coated on the inner and outer surfaces of the mixer.

3. The mixer assembly according to claim 1, characterized in that: The mixer comprises a first plate located in the housing, a second plate located downstream of the first plate along the airflow direction, and a third plate located downstream of the second plate along the airflow direction, the first plate comprising a blocking portion and a partition connected to the blocking portion, the mixer assembly comprising an air inlet cavity, an air outlet cavity and a mixing cavity communicating with the air inlet cavity and the air outlet cavity, the air inlet cavity, the mixing cavity and the air outlet cavity are used to allow exhaust gas to flow, the mixing cavity and the air inlet cavity are located on both sides of the partition, and the partition comprises a connecting hole communicating with the air inlet cavity and the mixing cavity; the housing comprises a mounting portion for mounting a urea nozzle, the urea nozzle is used to spray urea droplets into the mixing cavity, so that the exhaust gas entering the mixing cavity and the urea droplets collide with each other and mix in the mixing cavity; the mixer assembly further comprises a porous plate located in the mixing cavity and above the partition, the porous plate being provided with a plurality of urea crushing holes for crushing urea.

4. The mixer assembly according to claim 3, characterized in that: The blocking portion extends in a vertical direction, the partition portion extends in a horizontal direction, and the porous plate is parallel to the partition portion.

5. The mixer assembly according to claim 3, characterized in that: The second plate is provided with a first fixing portion fixed on the inner wall of the shell and a first arc-shaped protrusion protruding forward from the middle of the first fixing portion into the mixing chamber, and the first arc-shaped protrusion is provided with a plurality of first air flow holes; the second plate is provided with a first recessed space located behind the first arc-shaped protrusion; the third plate is provided with a second fixing portion fixed on the inner wall of the shell and a second arc-shaped protrusion protruding forward from the middle of the second fixing portion at least partially into the first recessed space, and the second arc-shaped protrusion is provided with a plurality of second air flow holes; the mixer assembly includes an arc-shaped cavity located between the first arc-shaped protrusion and the second arc-shaped protrusion.

6. The mixer assembly according to claim 5, characterized in that: The first fixing portion is provided with a first slot, and the first arc-shaped protruding portion is provided with a second slot; The partition is provided with a first protruding piece inserted into the first slot and a second protruding piece inserted into the second slot.

7. The mixer assembly according to claim 6, characterized in that: The partition portion is provided with a first arc-shaped groove that matches the shape of the first arc-shaped protrusion, and the second protrusion protrudes into the first arc-shaped groove.

8. The mixer assembly of claim 5, wherein: The first arc-shaped protrusion spans across the second plate in the vertical direction, and the first fixing portion is located on both sides of the first arc-shaped protrusion; The second arc-shaped protrusion does not cross the third plate along the vertical direction, and the second fixing portion is located around the second arc-shaped protrusion; The first fixing portion is provided with a plurality of first air flow holes; the second fixing portion is provided with a plurality of second air flow holes; The second arc-shaped protrusion is punched from the middle of the third plate, and the third plate is provided with a first tearing opening corresponding to the upper edge of the second arc-shaped protrusion and a second tearing opening corresponding to the lower edge of the second arc-shaped protrusion.

9. The mixer assembly of claim 5, wherein: The first fixing portion is provided with a third slot, the second arc-shaped protruding portion is provided with a fourth slot; the blocking portion is provided with a fifth slot; The perforated plate is provided with a third lug inserted into the third slot, a fourth lug inserted into the fourth slot, and a fifth lug inserted into the fifth slot; The perforated plate is provided with a second arc-shaped groove that matches the shape of the first arc-shaped protrusion, and the fourth protrusion protrudes into the second arc-shaped groove.

10. The mixer assembly of claim 3, wherein: The hydrophobic coating is coated on the outer surface of at least one of the shell, the first plate, the second plate, the third plate and the porous plate.

11. An exhaust gas post-treatment package, characterized in that: The invention comprises a diesel oxidation catalyst component, a diesel particulate trap component located downstream of the diesel oxidation catalyst component and connected to the diesel oxidation catalyst component, a mixer component located downstream of the diesel particulate trap component and connected to the diesel particulate trap component, and a selective catalytic reduction component located downstream of the mixer component and connected to the mixer component, wherein the mixer component is the mixer component according to any one of claims 1 to 10.

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